Frame for bicycle
A frame for a bicycle includes a front frame, a rear frame, an upper linkage, and a shock absorber. The rear frame is pivoted to the front frame at a main pivot axis. The upper linkage is pivoted to the front frame at a first pivot axis and is pivoted to the rear frame at a second pivot axis. The shock absorber is pivoted to the upper linkage at a third pivot axis and is pivoted to the front frame. When a compression ratio of the shock absorber is in a range between 0% and 60%, a distance variation between a pivot location of the rear frame at the second pivot axis and a pivot location of the rear frame at the main pivot axis reaches a maximum value thereof.
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This application claims the priority benefit of Taiwan application serial no. 106127988, filed on Aug. 17, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
BACKGROUND OF THE INVENTION Field of the InventionThe invention relates to a frame for a bicycle, and in particular, to a frame for a bicycle having a shock-absorbing function.
Description of Related ArtTo adapt to rugged road surfaces, a frame for a bicycle may be integrated with a shock absorber to provide adequate buffering. To integrate the shock absorber with the frame, it is required to design a plurality of pivots on the frame. However, during the shock absorbing process, it is difficult to avoid deformation of the frame. As time passes, fatigue of the frame is increased, and a lifetime of the frame is thus reduced.
SUMMARY OF THE INVENTIONThe invention provides a frame for a bicycle for reducing fatigue of the frame and thereby enhancing a lifetime of the frame.
The frame for a bicycle of the invention includes a front frame, a rear frame, an upper linkage, and a shock absorber. The rear frame is pivoted to the front frame at a main pivot axis. The upper linkage is pivoted to the front frame at a first pivot axis and is pivoted to the rear frame at a second pivot axis. The shock absorber is pivoted to the upper linkage at a third pivot axis and is pivoted to the front frame. When a compression ratio of the shock absorber is 0%, a distance variation between a pivot location of the rear frame at the second pivot axis and a pivot location of the rear frame at the main pivot axis is 0. When the compression ratio of the shock absorber is in a range between 0% and 60%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches a maximum value thereof.
In an embodiment of the invention, the shock absorber is pivoted to the front frame at the main pivot axis.
In an embodiment of the invention, the front frame includes a seat tube and a down tube, the rear frame includes a seat stay and a chain stay, the seat stay is fixed to the chain stay at a rear wheel center, the chain stay is pivoted to the down tube at the main pivot axis, the upper linkage is pivoted to the seat tube at the first pivot axis and is pivoted to the seat stay at the second pivot axis, the shock absorber is pivoted to the down tube, when the compression ratio of the shock absorber is 0%, a distance variation between a pivot location of the seat stay at the second pivot axis and a pivot location of the chain stay at the main pivot axis is 0, and when the compression ratio of the shock absorber is in the range between 0% and 60%, the distance variation between the pivot location of the seat stay at the second pivot axis and the pivot location of the chain stay at the main pivot axis reaches a maximum value thereof.
In an embodiment of the invention, the shock absorber is pivoted to the down tube at the main pivot axis.
In an embodiment of the invention, when the compression ratio of the shock absorber is in a range between 40% and 60%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches the maximum value thereof.
In an embodiment of the invention, when the compression ratio of the shock absorber is in a range between 45% and 55%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches the maximum value thereof.
In an embodiment of the invention, when the compression ratio of the shock absorber is 50%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches the maximum value thereof.
In an embodiment of the invention, when the compression ratio of the shock absorber is 0%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis is 0.
In an embodiment of the invention, when the compression ratio of the shock absorber is 100%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis is 0.
In an embodiment of the invention, when the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches the maximum value thereof, projections of the main pivot axis, the first pivot axis, and the second pivot axis on a geometric plane are located on a same straight line.
In an embodiment of the invention, a distance between the pivot location of the rear frame at the main pivot axis and the pivot location of the rear frame at the second pivot axis is equal to a distance between projections of the main pivot axis and the second pivot axis on a geometric plane, a distance between projections of the main pivot axis and the second pivot axis on the geometric plane is a first distance when the compression ratio of the shock absorber is 0%, a distance between projections of the main pivot axis and the second pivot axis on the geometric plane is a second distance when the shock absorber is compressed and projections of the main pivot axis, the first pivot axis and the second pivot axis on the geometric plane located on a same straight line, and the second distance minus the first distance is less than 4 mm.
In an embodiment of the invention, a distance between projections of the main pivot axis and the second pivot axis on a geometric plane under the compression ratio of the shock absorber is 60% is less than a distance between projections of the main pivot axis and the second pivot on the geometric plane under the compression ratio of the shock absorber is 35%.
In light of the above, in the invention, the compression ratio of the shock absorber is set by configuring the distance variation of the rear frame at the first pivot axis and the second pivot axis to reach the maximum value thereof, so as to reduce fatigue of the frame and thereby enhance the lifetime of the frame.
To provide a further understanding of the aforementioned and other features and advantages of the disclosure, exemplary embodiments, together with the reference drawings, are described in detail below.
Referring to
It is noted that when the compression ratio of the shock absorber 140 exceeds 60%, the rear frame 120 is subject to a greater force. At this time, if a deformation of the rear frame 120 (i.e., the distance variation between the pivot location of the rear frame 120 at the second pivot axis A2 and the pivot location of the rear frame 120 at the main pivot axis A0) also reaches a maximum value thereof, the rear frame 120 may be damaged. Therefore, in the present embodiment, when the compression ratio of the shock absorber 140 is in the range between 0% and 60%, the deformation of the rear frame 120 (i.e., the distance variation between the pivot location of the rear frame 120 at the second pivot axis A2 and the pivot location of the rear frame 120 at the main pivot axis A0) already reaches the maximum value thereof, so fatigue of the frame 100 (especially the rear frame 120) can be reduced to enhance a lifetime of the frame 100.
Referring to
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In the present embodiment, as shown in
In the present embodiment, when the compression ratio of the shock absorber 140 is in the range between 0% and 60%, the distance variation between the pivot location of the rear frame 120 (i.e., the seat stay 122) at the second pivot axis A2 and the pivot location of the rear frame 120 (i.e., the chain stay 124) at the main pivot axis A0 reaches the maximum value Vmax thereof.
In another embodiment, when the compression ratio of the shock absorber 140 is in a range between 40% and 60%, the distance variation between the pivot location of the rear frame 120 (i.e., the seat stay 122) at the second pivot axis A2 and the pivot location of the rear frame 120 (i.e., the chain stay 124) at the main pivot axis A0 reaches the maximum value Vmax thereof.
In another embodiment, when the compression ratio of the shock absorber 140 is in a range between 45% and 55%, the distance variation between the pivot location of the rear frame 120 (i.e., the seat stay 122) at the second pivot axis A2 and the pivot location of the rear frame 120 (i.e., the chain stay 124) at the main pivot axis A0 reaches the maximum value Vmax thereof.
In another embodiment, when the compression ratio of the shock absorber 140 is 50%, the distance variation between the pivot location of the rear frame 120 (i.e., the seat stay 122) at the second pivot axis A2 and the pivot location of the rear frame 120 (i.e., the chain stay 124) at the main pivot axis A0 reaches the maximum value Vmax thereof.
In the present embodiment, as shown in
Referring to
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In summary of the above, in the invention, the compression ratio of the shock absorber is set by configuring the distance variation of the rear frame at the first pivot axis and the second pivot axis to reach the maximum value thereof, so as to reduce fatigue of the frame and thereby enhance the lifetime of the frame.
Although the invention is disclosed as the embodiments above, the embodiments are not meant to limit the invention. Any person skilled in the art may make slight modifications and variations without departing from the spirit and scope of the invention. Therefore, the protection scope of the invention shall be defined by the claims attached below.
Claims
1. A frame for a bicycle comprising:
- a front frame;
- a rear frame pivoted to the front frame at a main pivot axis;
- an upper linkage pivoted to the front frame at a first pivot axis and pivoted to the rear frame at a second pivot axis; and
- a shock absorber pivoted to the upper linkage at a third pivot axis and pivoted to the front frame, wherein when a compression ratio of the shock absorber is in a range between 0% and 60%, a distance variation between a pivot location of the rear frame at the second pivot axis and a pivot location of the rear frame at the main pivot axis reaches a maximum value thereof.
2. The frame for a bicycle according to claim 1, wherein the shock absorber is pivoted to the front frame at the main pivot axis.
3. The frame for a bicycle according to claim 1, wherein the front frame comprises a seat tube and a down tube, the rear frame comprises a seat stay and a chain stay, the seat stay is fixed to the chain stay at a rear wheel center, the chain stay is pivoted to the down tube at the main pivot axis, the upper linkage is pivoted to the seat tube at the first pivot axis and is pivoted to the seat stay at the second pivot axis, the shock absorber is pivoted to the down tube, and when the compression ratio of the shock absorber is in the range between 0% and 60%, a distance variation between a pivot location of the seat stay at the second pivot axis and a pivot location of the chain stay at the main pivot axis reaches a maximum value thereof.
4. The frame for a bicycle according to claim 3, wherein the shock absorber is pivoted to the down tube at the main pivot axis.
5. The frame for a bicycle according to claim 1, wherein when the compression ratio of the shock absorber is in a range between 40% and 60%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches the maximum value thereof.
6. The frame for a bicycle according to claim 1, wherein when the compression ratio of the shock absorber is in a range between 45% and 55%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches the maximum value thereof.
7. The frame for a bicycle according to claim 1, wherein when the compression ratio of the shock absorber is 50%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches the maximum value thereof.
8. The frame for a bicycle according to claim 1, wherein when the compression ratio of the shock absorber is 0%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis is 0.
9. The frame for a bicycle according to claim 8, wherein when the compression ratio of the shock absorber is 100%, the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis is 0.
10. The frame for a bicycle according to claim 1, wherein when the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches the maximum value thereof, the main pivot axis, the first pivot axis, and the second pivot axis are located on a same geometric plane.
11. The frame for a bicycle according to claim 1, wherein when the distance variation between the pivot location of the rear frame at the second pivot axis and the pivot location of the rear frame at the main pivot axis reaches the maximum value thereof, projections of the main pivot axis, the first pivot axis, and the second pivot axis on a geometric plane are located on a same straight line.
12. The frame for a bicycle according to claim 1, wherein a distance between the pivot location of the rear frame at the main pivot axis and the pivot location of the rear frame at the second pivot axis is equal to a distance between projections of the main pivot axis and the second pivot axis on a geometric plane, the distance between projections of the main pivot axis and the second pivot axis on the geometric plane is a first distance when the compression ratio of the shock absorber is 0%, the distance between projections of the main pivot axis and the second pivot axis on the geometric plane is a second distance when the shock absorber is compressed and projections of the main pivot axis, the first pivot axis and the second pivot axis on the geometric plane located on a same straight line, and the second distance minus the first distance is less than 4 mm.
13. The frame for a bicycle according to claim 1, wherein a distance between projections of the main pivot axis and the second pivot axis on a geometric plane under the compression ratio of the shock absorber at 60% is less than the distance between projections of the main pivot axis and the second pivot axis on the geometric plane under the compression ratio of the shock absorber at 35%.
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Type: Grant
Filed: Jun 28, 2018
Date of Patent: Oct 27, 2020
Patent Publication Number: 20190054974
Assignee: Giant Manufacturing Co., Ltd. (Taichung)
Inventors: Ching-Sung Yi (Taichung), Shao-Chieh Liu (Taichung), Tzu-Pin Wu (Taichung)
Primary Examiner: Tony H Winner
Application Number: 16/021,033
International Classification: B62K 25/28 (20060101); B62K 3/02 (20060101);